I'm trying to educate myself more on how DNS works, and am struggling with trying out some options in my AWS VPC.

From the AWS Documentation on VPC, there are 2 DNS settings to choose from, DNS Hostnames & DNS Resolution. It states that the following will happen if they are disabled

If either or both of the attributes is set to false, the following occurs:

  1. Instances with a public IP address do not receive corresponding public DNS hostnames.
  2. The Amazon Route 53 Resolver cannot resolve Amazon-provided private DNS hostnames.

To try this out, I spun up an EC2 instance inside a VPC meeting this condition. In the EC2 console, it is correctly not advertising a DNS name. However, if I perform an nslookup on the ip, it gives a DNS name, seemingly conflicting with the documentation. enter image description here

Is this actually correct, and I am just thinking about this wrong? What is the point of just having it not advertised in the console, when it actually does seemingly exist behind the scenes? I feel like I am missing something pretty big here or mixing something up.



That's the PTR record set for that IP. Have a read through this to see what this is.

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